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AF 447 Search to resume

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AF 447 Search to resume

Old 31st May 2010, 04:51
  #1301 (permalink)  
 
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Bearfoil;
This looks definitely like a different spoiler than the one in the sea (your image post #1253).
All the photographs in post #1253 and post #1290, including that in the BEA's Interim Report are all of the same spoiler. Check all the pics carefully and the damage and tell-tale marks all match.

Other than the BEA photograph, all the other images were supplied directly to me from the ship which picked the spoiler up. My only problem is establishing exactly what spoiler it is, as my initial impression was that it was the Starboard Outer, and I had recorded that in some graphics posted to the AF447 thread many moons ago. The BEA have since confused the issue with their caption.

mm43
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Old 31st May 2010, 05:41
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Chris Scott;
Belatedly realising the problem, the crew select turbulence-penetration Mach (stated to be M0.76 − that's good for an A320 but I don't have a figure for the A330).
The Airbus recommended turbulence penetration speed for the A330-200 at FL350 is M0.80 in ISA conditions; TAT -54.1°C. The forecast temp at FL350 was -46°C and probably rose considerably, so the -40C they mentioned was still a bit "low"!

mm43

Last edited by mm43; 31st May 2010 at 05:53.
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Old 31st May 2010, 07:34
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Hello,
Originally Posted by mm43
The Airbus recommended turbulence penetration speed for the A330-200 at FL350 is M0.80 in ISA conditions;
Added to that both Airbus/Air France recommended turbulence penetration mode is Autothrottles OFF while AF447 A/T was kicked OFF by systems at 02.10, consequently, she was certainly not in turbulence penetration mode/speed until this point. Moreover, at 02.10, more than half of the CB system was already crossed, they were not just penetrating it.
S~
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Old 31st May 2010, 08:31
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Originally Posted by takata
she was certainly not in turbulence penetration mode/speed until this point
However, from BEA's 2nd report:
The RTLU was found in its place in the fin and disassembled. An examination
was performed at the manufacturer’s and showed that it would allow travel
of the rudder measured as 7.9° +/- 0.1°. As an example, at FL350, this travel is
obtained for Mach 0.8 +/- 0.004, corresponding to a CAS of 272 +/- 2 kt.
HN39
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Old 31st May 2010, 09:15
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Hi HN39,
Originally Posted by HN39
However, from BEA's 2nd report:
The RTLU was found in its place in the fin and disassembled. An examination
was performed at the manufacturer’s and showed that it would allow travel
of the rudder measured as 7.9° +/- 0.1°. As an example, at FL350, this travel is
obtained for Mach 0.8 +/- 0.004, corresponding to a CAS of 272 +/- 2 kt.
You are right about its inferred speed, but it may be also due to other factors like weather avoidance as she was 3 nm west off track (going away or returning to flight plan). Nonetheless, ATHR engaged is possibly ruling out severe turbulences, IMHO.
S~
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Old 31st May 2010, 09:17
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kijangnim

fair point but does it alter the point that dynamically the forces acting on any component at failure may not be as first motion ?

Last edited by Mr Optimistic; 31st May 2010 at 09:18. Reason: for clarity, hopefully
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Old 31st May 2010, 09:22
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Chris Scott;

In your account of the BBC documentary on AF447:
Pilots slow to take throttles out of CLB gate, so thrust does not increase in time to stop the A/C stalling.
I wonder, did they mention stall warning, and why it was ignored?

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Old 31st May 2010, 09:51
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The program gave a mini-course on supercooled water and pitot heads, but said little or nothing about airframe icing while encountering the phenomenon.

Severe icing from supercooled droplets can be astonishingly sudden, and flying an aircraft in turbulence, with the added burden of ice, could be one reason the crew had difficulty in staying inside the envelope.


I thought the program was quite good. It did have periods of the daft background noises that they seem to think makes things a tad more dramatic, but I noticed this was cut to zero when something important was being said.

I still find it hard to see why we're relying on Black Boxes. Given the amount of data being sent to 'Company', I can't help feeling that total monitoring could be done via satellite these days. While in America, I spend ages chatting to people on Skype. I share this with 20+ million people - many enjoying modest video. If this can be done as a give-away, surely something as important as crew well-being and aircraft integrity could be transmitted in real-time.
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Old 31st May 2010, 10:02
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Hello Bear,
Originally Posted by Bearfoil
bonjour. I think no one is bullying anyone. A different point of view is not aggression.
I dont feel aggressed but, I won't pick up each of your previous comment underlying that investigation is not credible or "is trying to suggest such and such scenario" which otherwise main weakness is that it doesn't fit yours. My opinion is that so far, no "scenario" was really pushed ahead by the BEA, only its findings about wreckages and flight conditions without regards if it will make sense or not.
Originally Posted by Bearfoil
ACARS had one message left to send, as we know, there is that delay in transmission.
I never read something about that. Reports are saying that all ACARS transmitted by AF447 were received.
Originally Posted by Bearfoil
You speak of loss of Lateral control, but all that has been shown is Lateral failure of the VS mounts. When the mounts broke and when or if the VS was lost in flight has not been established.
I used other poster's words, but so far, I have certainly read that it was established by investigators that the tail was not lost in flight neither any main part of the airframe.
Originally Posted by Bearfoil
Just as the spoilers were deployed as a result of some effort to gain stable flight, (an opinion), the VS may have stayed on. It also may have separated. I have a theory as to what occurred, and it is based on what is publicly known.
Obviously, it is still the exact same theory I'm reading from you, starting post crash. Whatever was found later about this flight, I'm not sure you'll be able to reconsider your point anyway.
S~
Olivier

Last edited by takata; 31st May 2010 at 10:13.
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Old 31st May 2010, 13:53
  #1310 (permalink)  
 
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I'm no aeronautical engineer, but is it perhaps possible that both theories - in-flight breakup and intact impact with the water - are partly true? Would it be possible for the aircraft to lose the VS and perhaps the HS and some control surfaces due to overspeed or excessive control inputs, and then enter some kind of stall or spin and impact the water in the manner suggested by the report (high vertical speed, but not so high as to completely disintegrate everything)? Or would losing the VS at altitude inevitably lead to an in-flight breakup?

I still find it hard to see why we're relying on Black Boxes. Given the amount of data being sent to 'Company', I can't help feeling that total monitoring could be done via satellite these days. While in America, I spend ages chatting to people on Skype. I share this with 20+ million people - many enjoying modest video. If this can be done as a give-away, surely something as important as crew well-being and aircraft integrity could be transmitted in real-time.
The ACARS messages are actually extremely small in terms of data transmitted. This issue has been discussed elsewhere on this thread and the original AF447 thread. It boils down to this: with the existing infrastructure, it is not feasible to transmit the amount of data necessary to make a continuous recording of the flight parameters recorded by the FDR, still less to stream the multiple audio tracks from the CVR. It is not so much a matter of installing new technology into the airplanes, but of how to transmit the data, which would perhaps require new satellites and other very expensive bits of infrastructure.

Plus, pilots may object to the possibility of being micromanaged from the ground even as they fly, if all that data is being sent in real time to the home office.
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Old 31st May 2010, 14:18
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BBC scenario, recovery from FL350, terminal conditions

Doesn't it seem unlikely that any major control surface failed during a possible overspeed given the conditions of impact ("en ligne de vol", no roll, no yaw, no sideslip, slight nose up) described in the BEA reports ?
If we assume a high altitude upset (which I do), we have to explain why the recovery from cruise altitude has not been possible... and despite this, why the A/C impacted the surface with a terminal velocity mostly vertical (contradictory with a recovery about to be successfull), but not as high as in previous cases of high dive from cruise altitude. Doesn't the possibility raised by the BBC documentary (overcorrection in the recovery at low altitude, possible in the absence of alpha prot and low speed stability => secondary stall at low altitude) have the potential to explain both of these aspects ?
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Old 31st May 2010, 14:46
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Procedures

I have read the following in the A330-340 Flight Crew Training manual (perhaps not the latest version?)
"Triple IRS or ADR failure is very unlikely and is not displayed on the ECAM. Should a triple failure occur, two double failures would be displayed, i.e. ADR 1 + 2 FAULT and ADR 2 + 3 FAULT. The subsequent ECAM actions would give conflicting instructions. In this case, apply the QRH procedure for ADR 1 + 2 + 3 failure. This is one of the few cases where the crew will not follow the ECAM procedure."
So the crew is left with conflicting info and have to find the proper document BEFORE they act.

When it comes to the software and hardware used on AF447, the BEA reports are very silent. Why give details about engines and some other hardware, but noting about the FBW-system? E.g. the QF72 accident report made by Australians contain a lot of such inf.

Now I am awaiting the flogging.
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Old 31st May 2010, 15:13
  #1313 (permalink)  
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Greetings
Mr Optimistic I have great difficulties understanding your sentence , can you please be kind enough to elaborate a bit more

There is a VDO about the B767 Ethiopian ditching look at it to see the effect the engines have when ditching.
 
Old 31st May 2010, 15:54
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I cant quite believe it

Can any one equate the design strength of the VS with the max possible deceleration "G" in any sort of flat ditching, and the forward "G" required to permit a fin and rudder to rip clean off its fittings?
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Old 31st May 2010, 16:19
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Hi,
Originally Posted by Diversification
I have read the following in the A330-340 Flight Crew Training manual (perhaps not the latest version?)
"Triple IRS or ADR failure is very unlikely and is not displayed on the ECAM. Should a triple failure occur, two double failures would be displayed, i.e. ADR 1 + 2 FAULT and ADR 2 + 3 FAULT. The subsequent ECAM actions would give conflicting instructions. In this case, apply the QRH procedure for ADR 1 + 2 + 3 failure. This is one of the few cases where the crew will not follow the ECAM procedure."
So the crew is left with conflicting info and have to find the proper document BEFORE they act.
Well, ADR 1+2+3 FAULT is memory item (ADR DISAGREE). Then, just apply it.
When it comes to the software and hardware used on AF447, the BEA reports are very silent. Why give details about engines and some other hardware, but noting about the FBW-system? E.g. the QF72 accident report made by Australians contain a lot of such inf.
BEA's reports are only "interim" dealing with partial findings while final report will certainly deal with that in details if something relevant is to be said about it.
S~
Olivier
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Old 31st May 2010, 16:53
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Originally Posted by kijangnim
There is a VDO about the B767 Ethiopian ditching look at it to see the effect the engines have when ditching.
There is also many videos about Hudson's ditching showing that engines, when they hit water with wings level - contrary to this B767 case, are absorbing a lot of forward energy without breaking up the airframe.

From my understanding, in AF447 case, vertical speed would have to be much higher to break it up and for causing so much compression into the lower part of the airframe (including tailfin separation, rudder damages, killing passengers, etc.).

I'm not quite sure actually how to represent accuratelly this kind of impact (a kind of slow flat spin, wings level and tail down? or with high sinking rate, first hit with tail, nose high, killing forward speed then pankaking?)... low end rudder damages are quite serious, possibly caused by tailcone's failure at impact with water. I'm waiting for the BEA's video to figure it out one day.
S~
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Old 31st May 2010, 19:40
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Greetings TAKATA

Huge difference between choosing to ditch and preparing the Aircraft with the right configuration speed and attitude and falling from the sky ......
 
Old 31st May 2010, 19:55
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Hello,
Takata;


In a reply to Bearfoil you wrote:-
I never read something about that. Reports are saying that all ACARS transmitted by AF447 were received.
I think that Bear is referring to the following detail from page 36 (English version) of the BEA Interim Report No.2. The PRIM 1 and SEC 1 faults below are possibilities, but the MAINTENANCE STATUS ADR2 would have been sent (if possible to do so).

F/CTL PRIM 1 FAULT (2 h 13)
This message indicates that FCPC1 (PRIM 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at 2 h 13 min 45 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 45.

F/CTL SEC 1 FAULT (2 h 13)
This message indicates that FCSC1 (SEC 1) has stopped functioning. This shutdown may have been commanded or be the result of a failure. In the absence of an associated fault message, it is not possible to command a shutdown. However, a fault message that had not had sufficient time to be transmitted can not be excluded. Indeed, this message was received at2 h 13 min 51 and the last message at 2 h 14 min 26, whereas the fault message could have appeared up until 2 h 14 min 51.

MAINTENANCE STATUS ADR2 (2 h 14)
This message was received at 2 h 14 min 14 and a class 2 fault message should have been received between 2 h 15 min 00 and 2 h 15 min 14.

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Old 31st May 2010, 20:04
  #1319 (permalink)  
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PM1:

"Monsieur, the turbulences are increasing rapidly, what will you do?"

PM2: "I will wait until the auto pilot has had enough and cannot keep to its design limits, then we can catch the controls as they fall into our lap."

PM1: "Oui"

Of course NOT. The pilots were startled at dropout of Auto flight.

What caused the Trip? Was it a roll beyond 45 degrees? Had 447 sliced into a monster up elevator with the tip and then the rest of one wing? What is the definition of the "edge" of vertical development? Had she then recovered level flight upon complete entry into the vertical wind tunnel? Did the pilots reduce a/s to book penetration velocity? At lower mach, did she climb with the monster to 37, 38?

Did she then exit the vertical column into the monster's twin, the down cycle?
At reduced speed, heavy weight, and an AoA adjusted to the climb, did she break?

In the ensuing dive did she pick up sufficient velocity to reach a/s far in excess of critical? Down into thicker air, did the break take her vertical, or past it? This is all a possibility if the weather was dramatic enough. How many more times did she stall, partially recover, then break even deeper?

To me, it is the first transmission of ACARS that may have sealed 447's fate. Upset? By definition, of course. Stall? Certainly.

ICE? What if Ice wasn't involved? What do the pitots and ADIRU do with shear?
Does the computer know the difference between Unreliable AirSpeed and Discrepant readings that mimic it? Better question: had the computer been 'taught' the difference? Is sufficient Yaw possible in recovering from overbanking that engines and pitot(s) can be blanked? Long enough to cause Computer Fault/Fail?

bear (IMO) OTR for now, someone please save my seat.

Last edited by bearfoil; 31st May 2010 at 20:15.
 
Old 31st May 2010, 20:16
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Can anybody explain the reasons for the ongoing discussion about the possibility of an inflight breakup or a partial inflight breakup?

BEA was in most parts of the tragic events very common, in the part of impact with the water and the probable condition of the hull prior impact very specific. The result had its origin in the found pieces of wreckage and most probably some experts looking at those in person and detail (despite us looking only at pictures) came to strong results, leading to the statement of BEA.

So what is the real sense in turning this result over and over? Would it not be better to accept it for the moment until other information tells otherwise and go on from that point?

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